docs: def all_days(boo):
    """
    Return a list of all dates from 11/12/2015 to the present.
  
    Args:
      boo: if true, list contains Numbers (20151230); if false, list contains Strings ("2015-12-30")
    Returns:
      list of either Numbers or Strings
    """
    earliest = datetime.strptime(('2015-11-12').replace('-', ' '), '%Y %m %d')
    latest = datetime.strptime(datetime.today().date().isoformat().replace('-', ' '), '%Y %m %d')
    num_days = (latest - earliest).days + 1
    all_days = [latest - timedelta(days=x) for x in range(num_days)]
    all_days.reverse()
  
    output = []
  
    if boo:
      # Return as Integer, yyyymmdd
      for d in all_days:
        output.append(int(str(d).replace('-', '')[:8]))
    else:
      # Return as String, yyyy-mm-dd
      for d in all_days:
        output.append(str(d)[:10])
    return output